ahci: avoton port-disable reset-quirk

commit dbfe8ef5599a5370abc441fcdbb382b656563eb4 upstream.

Avoton AHCI occasionally sees drive probe timeouts at driver load time.
When this happens SCR_STATUS indicates device detected, but no D2H FIS
reception.  Reset the internal link state machines by bouncing
port-enable in the PCS register when this occurs.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
[bwh: Backported to 3.2:
 - Adjust context
 - Call ahci_start_engine() directly]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>